The applicant proposes to learn and apply the tools of cell biology and molecular biology to a research area relevant to human lung disease. A number of regulatory peptides with potent physiologic pro-inflammatory, and growth promoting effects have been localized to the lung. A neutral metalloendopeptidase (NEP) appears to play a key role in degrading many of these peptides. The modulation of NEP will thus likely impact on the extent of the peptides' effects. NEP has recently been localized to the lung and evidence suggests that it is relevant to reactive airways disease. The long term objective is to understand the role and regulation of NEP in normal and diseased human airways. The specific aims of this proposal are to: 1) Fully characterize the purified human lung NEP from a structural, functional, and immunological standpoint. 2) Clone the gene from human cDNA and genomic libraries. The deduced amino acid sequence will likely provide additional information on the structure and function of the enzyme. This work will also provide the tools necessary to examine regulation of NEP at the transcriptional level. 3) Comprehensively assess modulation of epithelial cell NEP from the transcriptional to post-translational level. This work will consist of three major thrusts. The first will be a systematic screening of potential modulating factors in epithelial cell cultures. The second will be an examination of the effects of specific modulating factors on synthesis and degradation of NEP utilizing metabolic labelling and immunoprecipitation. The final thrust will be an incorporation of the DNA probe into the studies for an assessment of transcriptional regulation. The environment at the University of Utah is ideal for developing the investigative career of the applicant. Within the Pulmonary Division, or closely aligned, are a capable group of investigators with a wide range of interests from basic biochemistry, immunology, and molecular biology to physics and clinical physiology. Pulmonary research conferences, seminars, and journal clubs foster open communication in the Division. The sponsors of this proposal, Dr. John Hoidal and Dr. Ray White, are highly productive investigators with an excellent track record in developing young people. The University of Utah is particularly strong in the area of molecular biology and this proposal taps that potential. Through the application of the techniques of molecular biology to this proposal, the interaction with other basic science faculty and trainees with similar interests, and graduate course work, the applicant will gain a solid foundation in molecular biology.